ESP32-WROOM-32D dev board upload over UART

[fanzypantz]

I've been trying to program an ESP32D with an CH340G TTL converter, and I can read the serial print out fine, but when I'm trying to upload with my current setup on the development board, I can't connect. The buttons added in the schematic works fine when plugged into USB, but not whenever running directly on 3 or 5v power without USB and TX/RX from the USB device. From what I've seen of other programming tutorials, my schematic would work fine, but could the development board have something that blocks me from doing UART programming? like the 0.1uF capacitor on IO0?

The ESP32 bit of my board. The other two TX/RX on 16/17 is connected to a modbus controller(removed them to try).

[therealergo]

What exactly are you seeing on the serial terminal? Is the chip actually in download mode when you try to flash it? Do you have a ground connected to the TTL converter?

In order to be reprogrammed, the programmer will usually put the chip in download mode by resetting the chip while holding GPIO0 low. This is done automatically using the RTS/CTS modem lines with most ESP32 programmers. There's more details here: https://github.com/espressif/esptool/wi ... bootloader. Since you don't have those lines, you'll have to put the chip into download mode manually with the two buttons.

[fanzypantz]

I'm seeing the regular serial printout when the TX/RX is connected, when the program already on there is running. The TTL has common ground with the ESP32.

I noticed when I tried to flash over USB if anything is connected into the RX GPIO(this time a LoRa reciever), the Boot button (on the devkit, not the "new") alone wont let me into programming mode. That would be: holding down both buttons, then release EN until the connecting dots stop going like normal right? I ordered an CP2102 instead as it has a DIR pin, hoping that would work better to flash it.